[ANN] feature/instdir pushed to master

hello, good people,

i've just pushed Matúš' feature/instdir branch to master, which makes
the "instdir" an actually runnable office installation.

"dev-install" is no longer executed as part of a "make check", instead
the subsequent tests run against the "instdir".

this has been tested on Windows and Linux but _not_ on Mac where it will
probably fail horribly; if you don't feel like debugging build problems
you should probably delay pulling for a few days.  also, somebody with a
Mac needs to fix it since i can't run "subsequentcheck" remotely.

there will be some further build system cleanup this week, especially
removing the (currently) triplicate storage of link targets (iirc Bjoern
has something in gerrit for that...).

PS: you should be especially afraid since i've seen myself forced to
cargo-cult several, perhaps more than 10, lines of Perl for this
(naturally without understanding what any of it does)